Atranorin - An Interesting Lichen Secondary Metabolite

Abstract

In conclusion, atranorin seems to be an interesting lichen substance, which needs to be investigated in more detail in order to allow further applications, e.g. in pharmacy, medicine or cosmetology.

Lichens as a source of chemical compounds with anti-inflammatory activity

“…Lichens are an interesting taxonomic group; the organisms composed of cells of algae and fungi producing specific compounds, rare among the substances of natural origin, belong to this group. Their various biological properties include antimicrobial activity, known for a long time, as well as, researched in recent years, antioxidant and antitumor properties, resulting in inhibiting enzymes, antidiabetic, analgesic and anti-inflammatory activities [2,3]. The following paper is a review of the research on the little-known anti-inflammatory properties of lichens, drawing attention to the diversity of lichen substances, and effect of the individual compounds and extracts, whose inhibitory effect on the inflammatory processes was confirmed in vitro and in vivo.…”

Incomplete degradation of lichen usnic acid and atranorin in Svalbard reindeer (Rangifer tarandus platyrhynchus)

“…Rain and snow have not dissolved or washed out these metabolites from the faecal material and have not lowered their concentration in our samples. Storeheier et al (2002) reported the medium range of digestibility of different lichen species in ruminal inoculum in vitro to be between 41 and 78%, while Sundset et al (2010) reported the digestibility of lichens eaten by reindeer to amount to approximately 74%. This indicates that the total digestion of lichens may also influence the digestibility of secondary metabolites inside the lichen thalli.…”

“…Atranorin is antibacterial, but its toxicity has not been shown in animal models so far (De Melo et al 2011), while usnic acid can be toxic to both animals and humans (Dailey et al 2008) and even lethal in high doses, as shown for sheep (Durazo et al 2004). Still lichens may contribute more than 50% of the winter diet of reindeer in Subarctic and Arctic areas where lichens are an abundant part of the vegetation (Borch-Iohnsen et al 1996;Svihus & Holand 2000;Storeheier et al 2002;Denryter et al 2017). It is not fully understood how reindeer cope with such high intakes of lichen secondary compounds.…”

“…However, if not degraded or only partly degraded, and not absorbed, the secondary compounds will appear in the faeces. In general, lichens are low in proteins but contain large amounts of polysaccharides and are easily digested by reindeer, as long as the rumen microflora has had time to adapt to the substrate (Storeheier et al 2002). The bacterial and archaeal profiles in the rumen and cecum of Eurasian tundra reindeer (Rangifer tarandus tarandus) in Norway change significantly in response to a pure lichen diet compared to a concentrate reindeer feed (Salgado-Flores et al 2016).…”

HPLC determination of phenolic compounds content in Parmelia sulcata and Parmelia vagans thalli

“…According to the literature data, these lichens contain polysaccharides, anthraquinones, carotenoids, diterpenoids and steroids, aliphatic acids, amino acids, however, compounds of much interest are the secondary metabolites of phenolic nature -lichen acids, which possess a wide range of biological activity (Sharma 2013;Shcherbakova et al 2013;Gomez-Serranillos et al 2014;Bhattacharyya 2016;Studzińska-Sroka et al 2017).…”